The release-key.asc file contain the release key for this archive. Download
and use in the following way:
wget http://apt.inguza.net/release-key.asc
cat release-key.asc | sudo apt-key add -
After this is done you can add the following line to /etc/apt/sources.list
deb http://apt.inguza.net squeeze main
or
deb http://apt.inguza.net wheezy main
i386 and amd64 architectures supported